Area forecast discussion
National Weather Service Lincoln Illinois
632 am CDT sun may 19 2013
Discussion...
issued 330 am CDT sun may 19 2013
Short term...today through Wednesday night
Will continue mention of patchy fog over eastern Illinois east of I-57
into middle morning and has been dense at times near the Wabash River
at Lawrenceville. Upper level ridge building into Illinois today will
bring a very warm and more humid day to central/southeast Illinois with highs
in the middle to upper 80s. Dewpoints in the lower 60s to rise into
the upper 60s to near 70f this afternoon with airmass getting
increasingly more unstable. One frontal boundary was NE of central
Illinois from central Indiana into NE Illinois and southern Minnesota. Another warm
front over southern MO to near the Kentucky/Tennessee border will lift
northward across central/southeast Illinois during this afternoon and will
develop isolated to scattered showers and thunderstorms today over
central and SW areas especially this afternoon. Another chance of
showers and thunderstorms arrives tonight as short wave energy
ejects east-northeast from the Central Plains toward western Illinois especially
from I-55 west where Storm Prediction Center has a slight risk of severe storms for
15% risk of large hail and damaging wind gusts and 2% risk of a
tornado.
Another slight risk of severe storms Monday afternoon and Monday evening
from Champaign to Taylorville west. Models take cutoff upper level
low from Wyoming slowly east across the northern plains early this week
reaching eastern South Dakota by sunset Monday and moving very little on Tuesday.
Much of Illinois is in a slight risk of severe storms Tuesday
afternoon/evening due to slow movement of storm system to our northwest.
Central/southeast Illinois stays in unstable warm sector with very warm and
humid air. Highs Monday in the middle to upper 80s again and low to
middle 80s on Tuesday and could be warmer especially over eastern Illinois if
we get enough sunshine. Question to chances of severe storms next
few days is amount of heating/sunshine we can get to give a more
unstable airmass. Have some wind shear next few days though more
unidirectional by Tuesday. Have chances of showers/thunderstorms
through middle week with best chances Tuesday-Wednesday as upper level low
moves east into northern Illinois/southern WI Wednesday. Risk of severe storms
appears to shift east of Illinois Wednesday but if system moves slower...eastern
and southeast Illinois may still be a risk of a few strong to severe storms
Wednesday.
Long term...Thursday through Sunday
Upper level trough over the Great Lakes and Ohio Valley Thursday lingers
a chance of showers and isolated thunderstorms over
central/eastern Illinois with cooler temperatures with highs in the low
to middle 70s central Illinois and middle to upper 70s in southeast Illinois. Dry
conditions should finally return to Illinois by Friday and Friday night
as 1030 mb high pressure settles into the Great Lakes region.
Models that appeared to be dry for the end of the week...now have
different solutions especially ecwmf which is bringing quantitative precipitation forecast into Illinois
as early as Sat afternoon into Sunday. GFS model is still
generally dry with upper level ridging moving back toward Illinois. Will
trim probability of precipitation to slight chances from Sat afternoon into Sunday.
07
&&
Aviation...
issued 632 am CDT sun may 19 2013
Some light fog...MVFR conditions...is possible at all sites
except for spi this morning. Bmi/Dec/cmi could see brief IFR visible
conditions as well for couple of hours this morning. Then VFR
conditions are expected at all sites remainder of the forecast
period. Biggest issue is when will thunderstorms redevelop and
move across the area. A warm front will be moving north through
the area this afternoon and some thunderstorms could develop
then...but lots of uncertainty on this so will leave it out for
now. Seems biggest chance of thunderstorms will be later tonight
when remnants of the convection that develops well west of the
area this afternoon will move into the state. This appears to
occur after midnight. For now will just have thunderstorms in the vicinity at each site
starting at 02z or 03z. Later forecast can then refine when
details are better known. Winds will be southeast to south through
the period.
Auten
&&
Ilx watches/warnings/advisories...
none.
&&
$$
